The present invention relates to diagnostics for use in industrial processes, and in some embodiments particularly, to systems and methods for detecting fouling and corrosion in an industrial process.
Corrosion and fouling have been a longstanding concern in many industries. In the process industry, corrosion and fouling cause wall thinning and reduction of flow area, both of which are detrimental to the performance of pipes, conduits, cylinders, tanks, pressure vessels and the like. Additionally, corrosion and fouling may cause fixed equipment attached to the system to break down and fail. Depending on the system, such failures can be very costly.
Various techniques have been adopted to try to detect corrosion and/or fouling prior to equipment failure. One technique involves attaching a specialized corrosion and/or fouling detection device to the outside of the process structure, directing an ultrasonic signal transverse to the direction of flow through the wall of the structure, and detecting the reflected ultrasonic signal to measure changes in wall thickness over time, which may be indicative of plugging or fouling. Another technique involves directing an ultrasonic signal into a wall of a fluid-filled container. The ultrasonic signal propagates from a transmitting transducer to a receiving transducer. Analysis of the received waves determines the presence of corrosion on the inner wall. A third technique involves introducing an acoustic device into the fluid flow, which can be either fixed in place or floating like debris in the fluid, from which an acoustic signature of the pipe wall can be derived.
Additionally, a number of externally mounted detection devices have been proposed for detecting noise signature changes in fixed equipment. It is known in the art that as process fluid flows through any of the various types of fixed equipment (boilers, mixers, heat exchangers, valves, and the like), a process noise signature is produced. As plugging, fouling or corrosion occurs, the process noise signature changes.
Unfortunately, conventional fouling and corrosion detection devices and techniques require specialized detection equipment, which are separate from existing monitoring and control equipment. Such equipment can be expensive to add to an existing monitoring and control system. There remains an on-going need in the art for a system and method for detecting fouling and/or corrosion of fixed equipment that does not require specialized equipment. Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.